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Research subject: It is not an easy task to get a suitable model of polymerization due to complex mechanism and kinetic of such processes. Polymerization temperature, as an intermediate variable between determining final polymer properties, is a good selection to be controlled. Fuzzy logic has ability to be applied to processes with unknown or less informed dynamics.
Research approach: In this research, control of semi batch poly(ethylene terephthalate) reactor temperature was studied. To do so, error and error variation were calculated using measured reactor temperature. Error and error variation were fuzzified using triangular membership functions. Five and three fuzzy sets were introduced to fuzzify error and error variation, respectively. Hence, fifteen rules were defined. Five fuzzy sets were defined to quantify these fifteen rules. Weight average defuzzification method was applied to calculate necessary heat to the reactor. Poly(ethylene terephthalate) was synthesized in a semi batch reactor based on a two steps method. It is possible to monitor temperature, pressure, rotation speed and mixing torque in this set up.
Main results: Produced water during esterification determines reaction advancement. In polycondensation step, mixing torque determines end of the process. Linguistic based fuzzy rules were applied to both steps. Reference temperatures were 230^oC and 260^oC, respectively. Reactor temperature was controlled with 1-2^oC precision. Control logic was applied using C#.net real time programming.

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Research subject: In the present study, a number of linear and long-chain branched copolyesters, poly (butylene succinate-co-ethylene terephthalate) (PBSET), were synthesized. Hence, effect of branching agent introduction was studied. Such a copolyesters, mostly aliphatic polyesters, may be applied in biomaterial fields. Adding aromatic section and branching agent have great effects on properties.
Research approach: All polyesters were synthesized via a two-step method: esterification and polycondensation. All samples were produced in a laboratory scale set-up. First, prepolymers of two monomers were produced, separately. Then, required amount of each prepolymer were poured in the reactor and catalyst and thermal stabilizer were added and polycondensation reaction was performed. Pentaerythritol (PER) and trimellitic anhydride (TMA) were used as branching agents during synthesis. Microstructure of the copolyesters were characterized by ATR-FTIR and ¹³CNMR. Crystallinity, using XRD, and mechanical properties were studied, too.  Even small amount of branching agent has a great effect on properties. 0.4 mol% of PER and 0.4 and 0.6 mol% of TMA were incorporated.
Main results: Intrinsic viscosities of samples indicate that high molecular weight, about 38000 g/mol, were reached. ATR-FTIR spectra proves polyester synthesis. ¹³CNMR spectra shows incorporation of branching agent in polyester chain. Based on the XRD spectra, branching has no effect on the crystal type and type of crystal was unchanged. However, Crystallinity is decreased with branching. Mechanical properties are under serious effect of branching agent addition. It was observed that elongation at break and tensile strength were increased up to 400% and 200%, respectively. Hence, these branched copolyesters were synthesized and structure, crystallinity and mechanical properties were studied.

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Abstract The Novel Noghreh, daughter of Kabul River, written by Humaira Qaderi, one of the young and proposed Afghanistan novilist that it is one of the most important novels of contemporary Afghanistan. Here social and political issues have been addressed from the standpoint of women, with a focus on women. The purpose of this article is to study the status and role of Afghan women in contemporary Persian fiction in this country and explore this novel via Critical Discourse Analysis. After the introduction of research methods and theoretical bases of Norman Fairclough, we will analysis the text in three stages. The results of our analysis show that context of novel representations two types of conflict: the Conflict between traditional patriarchal discourses and discourses of femininity (feminist) and the contrast between the intellectual discourse and the discourse of power. The author represents all events of the story about political and social issues in a particular period of history; thus, the method of analysis components of Critical Discourse Analysis, besides to the specific and targeted approach to the representation of the events of the story in author perspectives, introduced reader with some of the developments in this story that its role is played by the women in Afghan society. Author's emphasis is on a particular period of history than any other time also reflects national trends and anti-authoritarian and colonial. Due to the presence of foreign forces and interference potential and secretly warns and in addition to the design of social and emotional issues of women, her apparent bias against traditional patriarchal discourse shows.

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Tornado is a destructive phenomenon which causes severe damage every year. To improve resistance of structures which face tornado, the flow field and factors which affect damage patterns of tornado need to be investigated. In this paper, numerical simulations of stationary and translating tornadoes are carried out using Ward-type simulator results and large eddy turbulence model. Validation for stationary case has been done with experimental work of Baker. The effects of peak winds, duration of intense winds and acceleration of translating tornado on damage patterns have been investigated. Results show that destruction is more intense at the side of the tornado that translational velocity and tangential wind velocity are added up. Moreover, peak wind velocity and duration of intense winds are important factors that have important effects on the destruction pattern of tall structures. However, the value of the translational acceleration of tornado is important for the design of all structures regardless of their heights.

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Variation of the cross-sectional area of a channel affects the flow field and, therefore, convective heat transfer between the fluid and channel walls. In this paper, a geometrical model is proposed for a wavy channel carrying steady laminar flow of an incompressible fluid. The two-dimensional channel is modeled as a combination of a number of subsonic diffusers and nozzles. Effects of the geometrical characteristics such as length, boundary shape and symmetry of the channel, which describe the shape of these nozzles and diffusers, are investigated. Numerical studies at Re=200 show that the shape of the wall does not dramatically affect the convection heat transfer rate in the steady laminar regime. However, optimization studies can be carried out to change the shape of the channel and improve the average Nusselt number to some extent. It is shown that the average Nusselt number increases with the increase of the length of the diffuser part, but the asymmetry of the channel might increase or decrease the average Nusselt number. Finally, a genetic algorithm is introduced and used to optimize the geometrical parameters which describe the aforementioned nozzles and diffusers and, hence, the shape of the channel.

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In this paper an improved immersed boundary method is used for simulating sinusoidal pitching oscillations of a symmetric airfoil. Immersed boundary methods because of using a fixed Cartsian grid are well suited for such moving boundary problems. Two test cases are used to validate the proposed method and the effects of oscillation frequency and amplitude on the flow field are investigated. Flow field vorticity and kinetic energy contours are reported in this paper. It is found that the deflected wake start to be appeared for Strouhal number more than 0.4 at a fixed pitching amplitude 0.71. A chaotic flow can be observed at oscillation amplitude 2.80, for a fixed Strouhal number, 0.22. Kintic energy contour shows that for Strouhal number 0.1, the airfoil performs work and transfers momentum to flow but the fluid energy loss due to the enlargement of flow separation zone decreases the momentum and kinetic energy behind the airfoil. Deficit momentum and kinetic energy behind the airfoil results in drag force increasing. By increasing the oscillation frequency and amplitude more momentum transfers to flow filed behind the airfoil which results in drag force decreasing.

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Numerous models have been proposed to incorporate various equations of state (EOS) into the pseudo potential model. This paper presents an investigation of different EOS types based on the Gong and Cheng model in multiphase-single component flows by the lattice Boltzmann method. Primarily, it is conducted to investigate eight EOS’s classified in four categories; the Shan- Chen EOS, the cubic EOS, the non-cubic EOS, and the cubic and non-cubic combination EOS. The results show that each EOS type results in producing relatively similar spurious currents and has a maximum achievable density ratio. Although by choosing a proper beta parameter for every EOS the simulation errors decrease dramatically, our results show it is impossible to set a constant parameter for the non-cubic EOS. Therefore, a new equation is introduced to predict an efficient beta for the cubic and the Shan- Chen EOS’s. It is also found that the non-cubic, cubic, and non-cubic and cubic combination EOS’s have a wider temperature range and larger density ratios respectively. Hence, we determine a temperature dependent function for the beta parameter prediction instead of using a fixed value for the non-cubic EOS. The results are noticeably in better agreement with those of the Maxwell construction (theoretical results).

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One of the interesting and practical problems in thermo-fluid sciences is referred to finding the shape of a boundary on which a specific distribution of pressure, temperature or heat flux is known. Because solving such problems using experimental, semi-experimental and analytical methods is time-consuming or even impossible in some practical situations, myriad numerical methods have been introduced to solve surface shape design (SSD) problems. In all the numerical algorithms, an initial guess is modified through a numerical process until the desirable distribution of the target variable is achieved. All the numerical algorithms use three computational tools, i.e. grid generator, flow solver and shape updater to solve an SSD problem. In most of numerical algorithms, not only the three mentioned tools work separately but the shape updater is also not derived from the governing equations. In this article, to solve SSD problems containing convection heat transfer, a new shape design algorithm called direct design method is presented in which grid generator, flow solver and shape updater work simultaneously and also the shape updater is directly derived from the governing equations. Some SSD problems containing convection heat transfer in which instead of the boundary shape the distribution of the heat flux is known are solved using the proposed algorithm. The obtained results show the capability of the method in solving SSD problems containing internal convection heat transfer.

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Refrigerant is one of the most important parts in a refrigeration cycle. In many refrigeration cycles, especially in the natural gas processing industry, propane is used as refrigerant due to its desirable thermodynamic properties. There are two ways for transferring propane and butane gases from extraction point to the consumption site: a) Pipeline and b) liquefaction and transport in liquid form. The most profitable method for transporting large quantities of propane and butane gases is liquefaction and transport in liquid form using storage tanks. Liquefaction at atmospheric pressure is the most common method for transporting large quantities of gases using specifically designed refrigerated ships. In this paper, a gas refinery butane and propane liquefaction cycle is described first and then simulated in HYSYS software. Afterwards, Genetic Algorithm is used to minimize the total power consumption of the liquefaction cycle, through connecting HYSYS and MATLAB softwares. There are 13 variables and 13 constraints for compressors and heat exchangers in the formulation of the optimization problem. The results of this constrained optimization problem show that the power consumption can be reduced by 12.49% compared to the base case.

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The existence of huge gas resource in Iran and the global demand for the replacement of fossil fuels with this cleaner energy resource has caused that the large-scale gas export becomes an interesting topic. One of the methods for large-scale gas exports is liquefaction which is done by refrigeration cycle. Considering the importance of the efficient use and the reduction in energy consumption, particularly in large energy consumers like liquefaction plants, it is imperative to optimize the refrigeration cycles used in these plants. While there have been many studies focusing on the power consumption minimization of refrigeration cycles, however, in most of these studies the performance limitations of the refrigeration cycle components have not been considered. Therefore, the results of such studies are not practical for in-use refrigeration cycles in gas refineries. The main goal of this paper is to propose a systematic method to minimize the power consumption of in-use refrigeration cycles in gas liquefaction processes by taking into account the performance limitations of refrigeration cycle components and the interactions between the refrigeration cycle and the core process. In this regard, a combination of thermodynamic viewpoints and pinch technology is used as well as considering the above mentioned limitations, to express the multi-stage refrigeration cycles’ power consumption minimization problem as a function of several independent variables. Up to 15% reduction in the specific power consumption is achieved when the proposed method are implemented on the optimization of a typical in-use three-stage refrigeration cycle, used in a propane liquefaction plant.

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Background and Aim: Accurate estimation of the post-mortem interval (PMI) is a critical aspect of forensic investigations. Forensic entomology, which studies insect colonization and development on decomposing remains, contributes significantly to PMI determination. This study aimed to explore the succession patterns and species composition of insects of forensic importance during carcass decomposition in Ardabil City, northwest Iran.
Methods: Over one year (autumn 2021 to summer 2022), rabbit carcasses were used as decomposition models across different seasons. Adult and immature insects were collected daily throughout the five recognized decomposition stages. Collected specimens were preserved, mounted, and identified using standard entomological keys. Seasonal diversity and species abundance were assessed using the Shannon-Wiener index, while inter-seasonal similarities were measured with the Jaccard index.
Results: Twenty insect species were identified, with Diptera predominating in the early decomposition stages. The highest species richness (18 species) and diversity occurred in summer, where Lucilia sericata and other Calliphoridae were most common. Spring followed with 16 species, also dominated by L. sericata. Winter yielded only three species, mainly Calliphora vicina, and no insects were observed in autumn due to cold and snowfall.
Conclusion: Insect succession patterns vary by season and location, influencing PMI estimations. Species-level patterns are likely specific to local ecological conditions, emphasizing the importance of regional studies in forensic entomology.